Binocular display optical waveguide system and AR device

Abstract

The invention discloses a binocular display optical waveguide system and AR equipment. The binocular display optical waveguide system comprises a waveguide substrate, a coupling-in grating, a first prism array, a second prism array, a first coupling-out grating and a second coupling-out grating, the coupling-in grating is arranged at the central axis of the waveguide substrate; the first prism array and the second prism array are symmetrically arranged on the two sides of the coupling-in grating; the first out-coupling grating is arranged on one side of the first prism array, the second out-coupling grating is arranged on one side of the second prism array, and the first out-coupling grating and the second out-coupling grating are symmetrically arranged on the two sides of the in-coupling grating. Compared with the prior art, a binocular image synchronous display function of a single ray machine image source can be realized, visual coherence is improved, rainbow pattern interference can be effectively inhibited, the consistency of left and right eye field angles is ensured, the naturalness of image fusion is enhanced, the structural complexity and weight of AR equipment can be reduced, and the production cost of the AR equipment can be reduced.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and in particular to a binocular display optical waveguide system and AR device. Background Technology

[0002] In existing binocular display systems, each eye typically has an independent optical engine module for separate imaging to achieve stereoscopic vision. However, during the use of binocular display systems, the use of independent optical engines for each eye may lead to timing discrepancies between the optical engine modules, affecting image fusion. This may also result in unnatural diffraction rainbow fringes, impacting the visual experience. Furthermore, the assembly process of binocular display systems requires relatively more complex binocular image fusion calibration.

[0003] Therefore, it is necessary to provide a binocular display optical waveguide system and AR device to solve the above problems. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a binocular display optical waveguide system and AR device, which can realize the function of synchronous display of binocular images from a single optomechanical image source, effectively improve visual coherence, suppress rainbow interference, ensure the consistency of the field of view of both eyes, and enhance the naturalness of image fusion.

[0005] To achieve the above objectives, a first aspect of the present invention provides a binocular display optical waveguide system, comprising a waveguide substrate, a coupling grating, a first prism array, a second prism array, a first coupling grating, and a second coupling grating; the coupling grating is disposed at the central axis of the waveguide substrate; the first prism array and the second prism array are symmetrically disposed on both sides of the coupling grating; the first coupling grating is disposed on one side of the first prism array, and the second coupling grating is disposed on one side of the second prism array, and the first coupling grating and the second coupling grating are symmetrically disposed on both sides of the coupling grating.

[0006] In a preferred embodiment, the coupled grating includes a first grating vector K1 and a second grating vector K2, the grating vector of the first coupled grating is K3, the grating vector of the second coupled grating is K4, and a first axis is defined on the waveguide substrate, satisfying: K1+K3=0, |K2+K4|=|Kx| / 2, where Kx is the projection component of the incident light ray along the first axis on the waveguide substrate in K space.

[0007] In a preferred embodiment, the thickness of the waveguide substrate is h, and satisfies: 0.5mm≤h≤1.5mm.

[0008] In a preferred embodiment, the waveguide substrate includes a near-eye side and a far-eye side, and the coupling grating, the first coupling grating, and the second coupling grating are all disposed on the near-eye side. The coupling grating, the first coupling grating, and the second coupling grating are all transmission gratings.

[0009] In a preferred embodiment, the waveguide substrate includes a near-eye side and a far-eye side, and the coupling grating, the first coupling grating, and the second coupling grating are all disposed on the far-eye side. The coupling grating, the first coupling grating, and the second coupling grating are all reflective gratings.

[0010] In a preferred embodiment, the distance between the first coupling grating and the second coupling grating is D, and satisfies 60mm≤D≤73mm.

[0011] In a preferred embodiment, the binocular display waveguide system includes a first head-up region and a second head-up region located on the waveguide substrate, a first comfort region is formed above the first head-up region, and a second comfort region is formed above the second head-up region; a first coupling grating is located within the first comfort region; and a second coupling grating is located within the second comfort region.

[0012] In a preferred embodiment, the size of the first coupling grating is smaller than the size of the first comfort zone; the size of the second coupling grating is smaller than the size of the second comfort zone.

[0013] In a preferred embodiment, the coupling-in grating, the first coupling-out grating, and the second coupling-out grating are all one-dimensional gratings.

[0014] A second aspect of this application provides an AR device that includes the binocular display optical waveguide system of any of the foregoing embodiments.

[0015] The beneficial effects of this invention are as follows: by using a coupling grating to separate incident light into two beams of light with opposite propagation directions, it can realize the function of simultaneous display of binocular images from a single optomechanical image source, which can significantly improve visual coherence and comfort, effectively suppress the occurrence of diffraction rainbow patterns, improve visual clarity, and can relatively accurately match the field of view and spatial position, ensuring the consistency of the field of view of the left and right eyes and enhancing the naturalness of image fusion, thereby reducing the structural complexity and weight of AR devices and reducing the production cost of AR devices. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a binocular display optical waveguide system provided in an embodiment of the present invention.

[0017] Figure 2 The K-space wave vector distribution diagram of the binocular display optical waveguide system provided in the embodiment of the present invention. Detailed Implementation

[0018] In this invention, the terms "set up," "equipped with," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0019] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0020] Furthermore, some of the aforementioned terms, besides indicating direction or positional relationships, may also have other meanings. For example, the term "above" may, in certain circumstances, indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] The following is the content of the first aspect of this application: Please refer to Figure 1 This embodiment provides a binocular display optical waveguide system, which includes a waveguide substrate 1, a coupling grating 2, a first prism array 3, a second prism array 4, a first coupling grating 5, and a second coupling grating 6. The coupling grating 2 is disposed at the central axis of the waveguide substrate 1. The first prism array 3 and the second prism array 4 are symmetrically disposed on both sides of the coupling grating 2. The first coupling grating 5 is disposed on one side of the first prism array 3, and the second coupling grating 6 is disposed on one side of the second prism array 4, and the first coupling grating 5 and the second coupling grating 6 are symmetrically disposed on both sides of the coupling grating 2.

[0023] The coupling grating 2 separates the light emitted from the image source into a first light ray and a second light ray, and efficiently couples the first light ray and the second light ray into the waveguide substrate 1. The first prism array 3 receives the first light ray from the coupling grating 2 and transmits the light to the first output grating 5. The second prism array 4 receives the second light ray from the coupling grating 2 and transmits the light to the second output grating 6. The first output grating 5 couples the received light ray out of the waveguide substrate 1 and projects it onto the eye of one user, and the second output grating 6 couples the received light ray out of the waveguide substrate 1 and projects it onto the eye of the other user.

[0024] Specifically, the binocular display waveguide system is described using a Cartesian coordinate system, where the Z-axis is perpendicular to the plane of waveguide substrate 1 and points towards the thickness direction of waveguide substrate 1, and the plane formed by the X and Y axes coincides with the plane containing waveguide substrate 1. The grating periods of the coupling grating 2, the first coupling grating 5, and the second coupling grating 6 range from 200 nm to 800 nm. The angle between the first prism array 3 and the X-axis on the waveguide substrate 1 ranges from 10° to 50°. Since the second prism array 4 is symmetrically arranged with respect to the first prism array 3 about the coupling grating, the angle between the second prism array 4 and the X-axis on the waveguide substrate 1 also ranges from 10° to 50°. The horizontal centerline of the first coupling grating 5 coincides with the projection position of the user's gaze point in one eye onto the waveguide substrate 1, and the horizontal centerline of the second coupling grating 6 coincides with the projection position of the user's gaze point in the other eye onto the waveguide substrate 1.

[0025] The optical path principle of the binocular display waveguide system is as follows: When the binocular display device is in operation, a single optomechanical image source emits light carrying image information. This light is coupled by a coupling grating 2 and then separated into a first light ray and a second light ray. Both the first and second light rays are guided into the waveguide substrate 1 and propagate along a preset direction within the waveguide substrate 1 by total internal reflection. After being guided by the coupling grating 2, the first light ray enters the first prism array 3, and the second light ray enters the second prism array 4.

[0026] Within the first prism array 3, the first ray is reflected by the total internal reflection surface, changing its propagation direction. In this changed direction, the ray is further expanded by the pupil dilator structure. After passing through the first prism array 3, the first ray transforms into a third ray. A portion of this third ray continues to propagate forward in the waveguide substrate 1, while the other portion, through diffraction by the first coupling grating 5, transforms into a fifth ray and exits into one of the user's eyes.

[0027] Within the second prism array 4, the second ray is reflected by the total internal reflection surface, changing its propagation direction. Following this change, the ray is further expanded by the pupil dilator structure. After passing through the second prism array 4, the second ray transforms into a fourth ray. A portion of this fourth ray continues to propagate forward in the waveguide substrate 1, while the remaining portion, through diffraction by the second coupling grating 6, transforms into a sixth ray and exits into one of the user's eyes.

[0028] It is understandable that by setting the coupling grating 2, the incident light can be separated into two beams of light that propagate in opposite directions, so as to realize the binocular output of image information from a single optomechanical image source, thereby realizing the binocular image synchronous display function of a single optomechanical image source, which can significantly improve visual continuity and comfort.

[0029] For further details, please refer to... Figure 2 In one embodiment, the coupled grating 2 includes a first grating vector K1 and a second grating vector K2, the grating vector of the first coupled grating is K3, the grating vector of the second coupled grating is K4, and a first axis is defined on the waveguide substrate, satisfying: K1+K3=0, |K2+K4|=|Kx| / 2, where Kx is the projection component of the incident light ray along the first axis on the waveguide substrate in K space.

[0030] The grating vector is used to represent the control effect of each grating on the light wave vector. In K space, the control effect of the grating on the light wave vector is manifested as shifting the projection distribution of the light wave vector in K space along a specific direction by a vector K, and K=Gmλ / d (where G is the unit vector of the periodic direction of the grating, m is the diffraction secondary, λ is the wavelength of light in vacuum, and d is the grating period).

[0031] Specifically, to ensure the effectiveness of light reception by the user's eyes, the grating vectors of the input grating 2 and the first output grating 3 need to satisfy a closed loop, that is, the resultant vector of the grating vectors of the input grating 2 and the first output grating 5 is zero, and the magnitude of the resultant vector of the grating vectors of the input grating 2 and the second output grating 4 is equal to half of the component of the incident light projection in K space along the X-axis direction of the Cartesian coordinate system established on the waveguide substrate 1. The direction of this resultant vector is related to the preset operating level of the optical waveguide system.

[0032] The wave vector distribution of the incident light in K-space includes a first region S1 and a second region S2. The first region S1 corresponds to the incident light with a field of view of [-θ, 0], and the second region S2 corresponds to the incident light with a field of view of [0, θ]. According to the diffraction characteristics of the coupling grating 2, after the incident light passes through the coupling grating 2, it will produce -1st and +1st order diffracted light. The intensity of the -1st order diffracted light is mainly distributed in the field of view of [-θ, 0], and its wave vector distribution area moves to the third region S3 through the first grating vector K1. The intensity of the +1st order diffracted light is mainly distributed in the field of view of [0, θ], and its wave vector distribution area moves to the fourth region S4 through the second grating vector K2.

[0033] In the light guiding region, after light is incident on the first prism array 3 and the second prism array 4, the light is reflected by inclined surfaces arranged along the propagation direction in the first prism array 3 and the second prism array 4. The film layer of the inclined surface can control the proportion of reflected light, thereby allowing the reflected light to uniformly and fully cover the entire coupling region. The grating vector of the first coupling grating 5 is K3. After the light beam incident on the first coupling grating 5 is acted upon by the grating vector, the light beam is coupled out of the waveguide substrate and enters the eye of one of the users. At this time, the light wave vector distribution area in K space after the movement of the first coupling grating 5 is the first region S1. The grating vector of the second coupling grating 6 is K4. After the light beam incident on the second coupling grating 6 is acted upon by the grating vector, the light beam is coupled out of the waveguide substrate and enters the eye of the other user. At this time, the light wave vector distribution area in K space after the movement of the second coupling grating 6 is the first region S1.

[0034] It is understandable that by setting the grating vectors, the light wave vector distribution of the light rays entering the user's left and right eyes after passing through the first coupling grating 5 and the second coupling grating 6 can be in the same area, so that the light rays entering the user's left and right eyes have the same field of view range, ensuring the effectiveness of the light received by the user's eyes, and thus ensuring that the image information received by the left and right eyes is consistent.

[0035] Furthermore, in one embodiment, the thickness of the waveguide substrate 1 is h, and satisfies: 0.5mm ≤ h ≤ 1.5mm. It is understood that the thickness of the waveguide substrate 1, ranging from 0.5mm to 1.5mm, can effectively reduce the overall weight of the optical waveguide system, allowing for better installation within AR devices.

[0036] Furthermore, in one embodiment, the waveguide substrate 1 includes a near-eye side and a far-eye side. The coupling grating 2, the first coupling grating 5, and the second coupling grating 6 can all be disposed on the near-eye side or on the far-eye side, depending on the actual design requirements.

[0037] Specifically, when the insertion grating 2, the first output grating 5, and the second output grating 6 are all disposed on the near-eye side, they are all transmissive gratings. When the insertion grating 2, the first output grating 5, and the second output grating 6 are all disposed on the far-eye side, they are all reflective gratings.

[0038] Furthermore, in one embodiment, the distance between the first coupling grating 5 and the second coupling grating 6 is D, and satisfies 60mm≤D≤73mm. It is understood that controlling the distance between the first coupling grating 5 and the second coupling grating 6 within the range of 60mm to 73mm better conforms to the interpupillary distance of the human eye, thereby improving user viewing comfort.

[0039] Furthermore, existing near-eye display devices typically set the viewing area within the eye level. While this provides a relatively good viewing experience, because the coupling grating is located within the eye level, ambient light undergoes diffraction. After passing through the coupling grating, stray light enters the eye, causing users to observe rainbow patterns and thus affecting the user experience. Please refer to [reference needed]. Figure 1 In one embodiment, the binocular display waveguide system includes a first head-up view 7 and a second head-up view 8 located on a waveguide substrate 1. A first comfort zone 9 is formed above the first head-up view 7, and a second comfort zone 10 is formed above the second head-up view 8. A first coupling grating 5 is located within the first comfort zone 9, and a second coupling grating 6 is located within the second comfort zone 10.

[0040] The first head-up zone 7 and the second head-up zone 8 are the observable areas where the user's eyes receive the light output from the first coupling grating 5 and the second coupling grating 6, respectively. The first comfort zone 9 and the second comfort zone 10 are the areas on the first head-up zone 7 and the second head-up zone 8 where the user's eyes can comfortably observe the light.

[0041] Based on the characteristics of human vision, the comfortable viewing angle for upward viewing is generally between +0 and +30 degrees, while the comfortable viewing angle for horizontal viewing is approximately between -30 and +30 degrees, forming a visual field of about 60 degrees. Considering ergonomics and the size of the human pupil, to avoid overlap with the viewing area, the projection area of ​​the visual field range with a vertical viewing angle of +10 to +30 degrees and a horizontal viewing angle of -30 to +30 degrees on the waveguide substrate 1 can be set as the corresponding comfort zone.

[0042] Specifically, the size of the first coupling grating 5 is less than or equal to the size of the first comfort zone 9; the size of the second coupling grating 6 is less than or equal to the size of the second comfort zone 10. Preferably, the sizes of the first coupling grating 5 and the second coupling grating 6 are equal to the sizes of the first comfort zone 9 and the second comfort zone 10, respectively. It is easy to understand that having the sizes of the first coupling grating 5 and the second coupling grating 6 less than or equal to the sizes of the first comfort zone 9 and the second comfort zone 10, respectively, ensures that the first coupling grating 5 and the second coupling grating 6 are completely located within the first comfort zone 9 and the second comfort zone 10, respectively, thus balancing visual comfort and avoiding rainbow-like patterns.

[0043] It is understandable that by setting the first coupling grating 5 within the first comfort zone 9 on the first head-up viewing area 7 and setting the second coupling grating 6 within the second comfort zone 10 on the second head-up viewing area 8, diffraction rainbow stripes can be effectively avoided in the user's field of view when looking straight ahead, while not affecting the normal use of the near-eye display device in the head-up viewing area, and ensuring that visual imaging is achieved within the comfort zone, avoiding visual fatigue caused by excessive eye movement, and improving the user experience.

[0044] In summary, this application separates incident light into two beams with opposite propagation directions by using a coupling grating, enabling simultaneous display of binocular images from a single optomechanical image source. This significantly improves visual coherence and comfort, effectively suppresses the appearance of diffraction rainbow patterns, enhances visual clarity, and can relatively accurately match the field of view and spatial position, ensuring consistency between the left and right eye field of view and improving the naturalness of image fusion. This, in turn, reduces the structural complexity and weight of AR devices, thereby lowering their production costs.

[0045] The second aspect of this application provides an AR device that includes the binocular display waveguide system of any of the foregoing embodiments. It is understood that by setting up a binocular display waveguide system, the function of synchronous display of binocular images from a single optomechanical image source can be realized, thereby reducing the structural complexity and weight of the AR device and reducing the production cost of the AR device.

[0046] The above are merely specific embodiments of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A binocular display optical waveguide system, characterized in that, The device includes a waveguide substrate, a coupling grating, a first prism array, a second prism array, a first coupling grating, and a second coupling grating. The coupling grating is disposed at the central axis of the waveguide substrate. The first prism array and the second prism array are symmetrically disposed on both sides of the coupling grating. The first coupling grating is disposed on one side of the first prism array, and the second coupling grating is disposed on one side of the second prism array, with the first coupling grating and the second coupling grating symmetrically disposed on both sides of the coupling grating.

2. The binocular display optical waveguide system according to claim 1, characterized in that, The coupled-in grating includes a first grating vector K1 and a second grating vector K2. The grating vector of the first coupled-out grating is K3, and the grating vector of the second coupled-out grating is K4. A first axis is defined on the waveguide substrate, satisfying: K1+K3=0, |K2+K4|=|Kx| / 2, where Kx is the projection component of the incident light ray along the first axis on the waveguide substrate in K space.

3. The binocular display optical waveguide system according to claim 1, characterized in that, The thickness of the waveguide substrate is h, and satisfies: 0.5mm≤h≤1.5mm.

4. The binocular display optical waveguide system according to claim 1, characterized in that, The waveguide substrate includes a near-eye side and a far-eye side. The coupling grating, the first coupling grating, and the second coupling grating are all disposed on the near-eye side. The coupling grating, the first coupling grating, and the second coupling grating are all transmission gratings.

5. The binocular display optical waveguide system according to claim 1, characterized in that, The waveguide substrate includes a near-eye side and a far-eye side. The coupling grating, the first coupling grating, and the second coupling grating are all disposed on the far-eye side. The coupling grating, the first coupling grating, and the second coupling grating are all reflective gratings.

6. The binocular display optical waveguide system according to claim 1, characterized in that, The distance between the first and second coupled gratings is D, and satisfies 60mm≤D≤73mm.

7. The binocular display optical waveguide system according to claim 1, characterized in that, The binocular display waveguide system includes a first head-up viewing area and a second head-up viewing area located on the waveguide substrate. A first comfort zone is formed above the first head-up viewing area, and a second comfort zone is formed above the second head-up viewing area. The first coupling grating is located within the first comfort zone, and the second coupling grating is located within the second comfort zone.

8. The binocular display optical waveguide system according to claim 7, characterized in that, The size of the first coupling grating is less than or equal to the size of the first comfort zone; the size of the second coupling grating is less than or equal to the size of the second comfort zone.

9. The binocular display optical waveguide system according to claim 1, characterized in that, The grating period range of the coupled-in grating, the first coupled-out grating, and the second coupled-out grating is 200nm to 800nm.

10. An AR device, characterized in that, The binocular display optical waveguide system includes any one of claims 1 to 9.

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